~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/sctp/auth.c

Version: ~ [ linux-5.1-rc5 ] ~ [ linux-5.0.7 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.34 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.111 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.168 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.178 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.138 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.65 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* SCTP kernel implementation
  2  * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
  3  *
  4  * This file is part of the SCTP kernel implementation
  5  *
  6  * This SCTP implementation is free software;
  7  * you can redistribute it and/or modify it under the terms of
  8  * the GNU General Public License as published by
  9  * the Free Software Foundation; either version 2, or (at your option)
 10  * any later version.
 11  *
 12  * This SCTP implementation is distributed in the hope that it
 13  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 14  *                 ************************
 15  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 16  * See the GNU General Public License for more details.
 17  *
 18  * You should have received a copy of the GNU General Public License
 19  * along with GNU CC; see the file COPYING.  If not, see
 20  * <http://www.gnu.org/licenses/>.
 21  *
 22  * Please send any bug reports or fixes you make to the
 23  * email address(es):
 24  *    lksctp developers <linux-sctp@vger.kernel.org>
 25  *
 26  * Written or modified by:
 27  *   Vlad Yasevich     <vladislav.yasevich@hp.com>
 28  */
 29 
 30 #include <crypto/hash.h>
 31 #include <linux/slab.h>
 32 #include <linux/types.h>
 33 #include <linux/scatterlist.h>
 34 #include <net/sctp/sctp.h>
 35 #include <net/sctp/auth.h>
 36 
 37 static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
 38         {
 39                 /* id 0 is reserved.  as all 0 */
 40                 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
 41         },
 42         {
 43                 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
 44                 .hmac_name = "hmac(sha1)",
 45                 .hmac_len = SCTP_SHA1_SIG_SIZE,
 46         },
 47         {
 48                 /* id 2 is reserved as well */
 49                 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
 50         },
 51 #if IS_ENABLED(CONFIG_CRYPTO_SHA256)
 52         {
 53                 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
 54                 .hmac_name = "hmac(sha256)",
 55                 .hmac_len = SCTP_SHA256_SIG_SIZE,
 56         }
 57 #endif
 58 };
 59 
 60 
 61 void sctp_auth_key_put(struct sctp_auth_bytes *key)
 62 {
 63         if (!key)
 64                 return;
 65 
 66         if (refcount_dec_and_test(&key->refcnt)) {
 67                 kzfree(key);
 68                 SCTP_DBG_OBJCNT_DEC(keys);
 69         }
 70 }
 71 
 72 /* Create a new key structure of a given length */
 73 static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
 74 {
 75         struct sctp_auth_bytes *key;
 76 
 77         /* Verify that we are not going to overflow INT_MAX */
 78         if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
 79                 return NULL;
 80 
 81         /* Allocate the shared key */
 82         key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
 83         if (!key)
 84                 return NULL;
 85 
 86         key->len = key_len;
 87         refcount_set(&key->refcnt, 1);
 88         SCTP_DBG_OBJCNT_INC(keys);
 89 
 90         return key;
 91 }
 92 
 93 /* Create a new shared key container with a give key id */
 94 struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
 95 {
 96         struct sctp_shared_key *new;
 97 
 98         /* Allocate the shared key container */
 99         new = kzalloc(sizeof(struct sctp_shared_key), gfp);
100         if (!new)
101                 return NULL;
102 
103         INIT_LIST_HEAD(&new->key_list);
104         refcount_set(&new->refcnt, 1);
105         new->key_id = key_id;
106 
107         return new;
108 }
109 
110 /* Free the shared key structure */
111 static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
112 {
113         BUG_ON(!list_empty(&sh_key->key_list));
114         sctp_auth_key_put(sh_key->key);
115         sh_key->key = NULL;
116         kfree(sh_key);
117 }
118 
119 void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
120 {
121         if (refcount_dec_and_test(&sh_key->refcnt))
122                 sctp_auth_shkey_destroy(sh_key);
123 }
124 
125 void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
126 {
127         refcount_inc(&sh_key->refcnt);
128 }
129 
130 /* Destroy the entire key list.  This is done during the
131  * associon and endpoint free process.
132  */
133 void sctp_auth_destroy_keys(struct list_head *keys)
134 {
135         struct sctp_shared_key *ep_key;
136         struct sctp_shared_key *tmp;
137 
138         if (list_empty(keys))
139                 return;
140 
141         key_for_each_safe(ep_key, tmp, keys) {
142                 list_del_init(&ep_key->key_list);
143                 sctp_auth_shkey_release(ep_key);
144         }
145 }
146 
147 /* Compare two byte vectors as numbers.  Return values
148  * are:
149  *        0 - vectors are equal
150  *      < 0 - vector 1 is smaller than vector2
151  *      > 0 - vector 1 is greater than vector2
152  *
153  * Algorithm is:
154  *      This is performed by selecting the numerically smaller key vector...
155  *      If the key vectors are equal as numbers but differ in length ...
156  *      the shorter vector is considered smaller
157  *
158  * Examples (with small values):
159  *      000123456789 > 123456789 (first number is longer)
160  *      000123456789 < 234567891 (second number is larger numerically)
161  *      123456789 > 2345678      (first number is both larger & longer)
162  */
163 static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
164                               struct sctp_auth_bytes *vector2)
165 {
166         int diff;
167         int i;
168         const __u8 *longer;
169 
170         diff = vector1->len - vector2->len;
171         if (diff) {
172                 longer = (diff > 0) ? vector1->data : vector2->data;
173 
174                 /* Check to see if the longer number is
175                  * lead-zero padded.  If it is not, it
176                  * is automatically larger numerically.
177                  */
178                 for (i = 0; i < abs(diff); i++) {
179                         if (longer[i] != 0)
180                                 return diff;
181                 }
182         }
183 
184         /* lengths are the same, compare numbers */
185         return memcmp(vector1->data, vector2->data, vector1->len);
186 }
187 
188 /*
189  * Create a key vector as described in SCTP-AUTH, Section 6.1
190  *    The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
191  *    parameter sent by each endpoint are concatenated as byte vectors.
192  *    These parameters include the parameter type, parameter length, and
193  *    the parameter value, but padding is omitted; all padding MUST be
194  *    removed from this concatenation before proceeding with further
195  *    computation of keys.  Parameters which were not sent are simply
196  *    omitted from the concatenation process.  The resulting two vectors
197  *    are called the two key vectors.
198  */
199 static struct sctp_auth_bytes *sctp_auth_make_key_vector(
200                         struct sctp_random_param *random,
201                         struct sctp_chunks_param *chunks,
202                         struct sctp_hmac_algo_param *hmacs,
203                         gfp_t gfp)
204 {
205         struct sctp_auth_bytes *new;
206         __u32   len;
207         __u32   offset = 0;
208         __u16   random_len, hmacs_len, chunks_len = 0;
209 
210         random_len = ntohs(random->param_hdr.length);
211         hmacs_len = ntohs(hmacs->param_hdr.length);
212         if (chunks)
213                 chunks_len = ntohs(chunks->param_hdr.length);
214 
215         len = random_len + hmacs_len + chunks_len;
216 
217         new = sctp_auth_create_key(len, gfp);
218         if (!new)
219                 return NULL;
220 
221         memcpy(new->data, random, random_len);
222         offset += random_len;
223 
224         if (chunks) {
225                 memcpy(new->data + offset, chunks, chunks_len);
226                 offset += chunks_len;
227         }
228 
229         memcpy(new->data + offset, hmacs, hmacs_len);
230 
231         return new;
232 }
233 
234 
235 /* Make a key vector based on our local parameters */
236 static struct sctp_auth_bytes *sctp_auth_make_local_vector(
237                                     const struct sctp_association *asoc,
238                                     gfp_t gfp)
239 {
240         return sctp_auth_make_key_vector(
241                         (struct sctp_random_param *)asoc->c.auth_random,
242                         (struct sctp_chunks_param *)asoc->c.auth_chunks,
243                         (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
244 }
245 
246 /* Make a key vector based on peer's parameters */
247 static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
248                                     const struct sctp_association *asoc,
249                                     gfp_t gfp)
250 {
251         return sctp_auth_make_key_vector(asoc->peer.peer_random,
252                                          asoc->peer.peer_chunks,
253                                          asoc->peer.peer_hmacs,
254                                          gfp);
255 }
256 
257 
258 /* Set the value of the association shared key base on the parameters
259  * given.  The algorithm is:
260  *    From the endpoint pair shared keys and the key vectors the
261  *    association shared keys are computed.  This is performed by selecting
262  *    the numerically smaller key vector and concatenating it to the
263  *    endpoint pair shared key, and then concatenating the numerically
264  *    larger key vector to that.  The result of the concatenation is the
265  *    association shared key.
266  */
267 static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
268                         struct sctp_shared_key *ep_key,
269                         struct sctp_auth_bytes *first_vector,
270                         struct sctp_auth_bytes *last_vector,
271                         gfp_t gfp)
272 {
273         struct sctp_auth_bytes *secret;
274         __u32 offset = 0;
275         __u32 auth_len;
276 
277         auth_len = first_vector->len + last_vector->len;
278         if (ep_key->key)
279                 auth_len += ep_key->key->len;
280 
281         secret = sctp_auth_create_key(auth_len, gfp);
282         if (!secret)
283                 return NULL;
284 
285         if (ep_key->key) {
286                 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
287                 offset += ep_key->key->len;
288         }
289 
290         memcpy(secret->data + offset, first_vector->data, first_vector->len);
291         offset += first_vector->len;
292 
293         memcpy(secret->data + offset, last_vector->data, last_vector->len);
294 
295         return secret;
296 }
297 
298 /* Create an association shared key.  Follow the algorithm
299  * described in SCTP-AUTH, Section 6.1
300  */
301 static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
302                                  const struct sctp_association *asoc,
303                                  struct sctp_shared_key *ep_key,
304                                  gfp_t gfp)
305 {
306         struct sctp_auth_bytes *local_key_vector;
307         struct sctp_auth_bytes *peer_key_vector;
308         struct sctp_auth_bytes  *first_vector,
309                                 *last_vector;
310         struct sctp_auth_bytes  *secret = NULL;
311         int     cmp;
312 
313 
314         /* Now we need to build the key vectors
315          * SCTP-AUTH , Section 6.1
316          *    The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
317          *    parameter sent by each endpoint are concatenated as byte vectors.
318          *    These parameters include the parameter type, parameter length, and
319          *    the parameter value, but padding is omitted; all padding MUST be
320          *    removed from this concatenation before proceeding with further
321          *    computation of keys.  Parameters which were not sent are simply
322          *    omitted from the concatenation process.  The resulting two vectors
323          *    are called the two key vectors.
324          */
325 
326         local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
327         peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
328 
329         if (!peer_key_vector || !local_key_vector)
330                 goto out;
331 
332         /* Figure out the order in which the key_vectors will be
333          * added to the endpoint shared key.
334          * SCTP-AUTH, Section 6.1:
335          *   This is performed by selecting the numerically smaller key
336          *   vector and concatenating it to the endpoint pair shared
337          *   key, and then concatenating the numerically larger key
338          *   vector to that.  If the key vectors are equal as numbers
339          *   but differ in length, then the concatenation order is the
340          *   endpoint shared key, followed by the shorter key vector,
341          *   followed by the longer key vector.  Otherwise, the key
342          *   vectors are identical, and may be concatenated to the
343          *   endpoint pair key in any order.
344          */
345         cmp = sctp_auth_compare_vectors(local_key_vector,
346                                         peer_key_vector);
347         if (cmp < 0) {
348                 first_vector = local_key_vector;
349                 last_vector = peer_key_vector;
350         } else {
351                 first_vector = peer_key_vector;
352                 last_vector = local_key_vector;
353         }
354 
355         secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
356                                             gfp);
357 out:
358         sctp_auth_key_put(local_key_vector);
359         sctp_auth_key_put(peer_key_vector);
360 
361         return secret;
362 }
363 
364 /*
365  * Populate the association overlay list with the list
366  * from the endpoint.
367  */
368 int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
369                                 struct sctp_association *asoc,
370                                 gfp_t gfp)
371 {
372         struct sctp_shared_key *sh_key;
373         struct sctp_shared_key *new;
374 
375         BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
376 
377         key_for_each(sh_key, &ep->endpoint_shared_keys) {
378                 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
379                 if (!new)
380                         goto nomem;
381 
382                 new->key = sh_key->key;
383                 sctp_auth_key_hold(new->key);
384                 list_add(&new->key_list, &asoc->endpoint_shared_keys);
385         }
386 
387         return 0;
388 
389 nomem:
390         sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
391         return -ENOMEM;
392 }
393 
394 
395 /* Public interface to create the association shared key.
396  * See code above for the algorithm.
397  */
398 int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
399 {
400         struct sctp_auth_bytes  *secret;
401         struct sctp_shared_key *ep_key;
402         struct sctp_chunk *chunk;
403 
404         /* If we don't support AUTH, or peer is not capable
405          * we don't need to do anything.
406          */
407         if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
408                 return 0;
409 
410         /* If the key_id is non-zero and we couldn't find an
411          * endpoint pair shared key, we can't compute the
412          * secret.
413          * For key_id 0, endpoint pair shared key is a NULL key.
414          */
415         ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
416         BUG_ON(!ep_key);
417 
418         secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
419         if (!secret)
420                 return -ENOMEM;
421 
422         sctp_auth_key_put(asoc->asoc_shared_key);
423         asoc->asoc_shared_key = secret;
424         asoc->shkey = ep_key;
425 
426         /* Update send queue in case any chunk already in there now
427          * needs authenticating
428          */
429         list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
430                 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
431                         chunk->auth = 1;
432                         if (!chunk->shkey) {
433                                 chunk->shkey = asoc->shkey;
434                                 sctp_auth_shkey_hold(chunk->shkey);
435                         }
436                 }
437         }
438 
439         return 0;
440 }
441 
442 
443 /* Find the endpoint pair shared key based on the key_id */
444 struct sctp_shared_key *sctp_auth_get_shkey(
445                                 const struct sctp_association *asoc,
446                                 __u16 key_id)
447 {
448         struct sctp_shared_key *key;
449 
450         /* First search associations set of endpoint pair shared keys */
451         key_for_each(key, &asoc->endpoint_shared_keys) {
452                 if (key->key_id == key_id) {
453                         if (!key->deactivated)
454                                 return key;
455                         break;
456                 }
457         }
458 
459         return NULL;
460 }
461 
462 /*
463  * Initialize all the possible digest transforms that we can use.  Right now
464  * now, the supported digests are SHA1 and SHA256.  We do this here once
465  * because of the restrictiong that transforms may only be allocated in
466  * user context.  This forces us to pre-allocated all possible transforms
467  * at the endpoint init time.
468  */
469 int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
470 {
471         struct crypto_shash *tfm = NULL;
472         __u16   id;
473 
474         /* If the transforms are already allocated, we are done */
475         if (ep->auth_hmacs)
476                 return 0;
477 
478         /* Allocated the array of pointers to transorms */
479         ep->auth_hmacs = kcalloc(SCTP_AUTH_NUM_HMACS,
480                                  sizeof(struct crypto_shash *),
481                                  gfp);
482         if (!ep->auth_hmacs)
483                 return -ENOMEM;
484 
485         for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
486 
487                 /* See is we support the id.  Supported IDs have name and
488                  * length fields set, so that we can allocated and use
489                  * them.  We can safely just check for name, for without the
490                  * name, we can't allocate the TFM.
491                  */
492                 if (!sctp_hmac_list[id].hmac_name)
493                         continue;
494 
495                 /* If this TFM has been allocated, we are all set */
496                 if (ep->auth_hmacs[id])
497                         continue;
498 
499                 /* Allocate the ID */
500                 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
501                 if (IS_ERR(tfm))
502                         goto out_err;
503 
504                 ep->auth_hmacs[id] = tfm;
505         }
506 
507         return 0;
508 
509 out_err:
510         /* Clean up any successful allocations */
511         sctp_auth_destroy_hmacs(ep->auth_hmacs);
512         return -ENOMEM;
513 }
514 
515 /* Destroy the hmac tfm array */
516 void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
517 {
518         int i;
519 
520         if (!auth_hmacs)
521                 return;
522 
523         for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
524                 crypto_free_shash(auth_hmacs[i]);
525         }
526         kfree(auth_hmacs);
527 }
528 
529 
530 struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
531 {
532         return &sctp_hmac_list[hmac_id];
533 }
534 
535 /* Get an hmac description information that we can use to build
536  * the AUTH chunk
537  */
538 struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
539 {
540         struct sctp_hmac_algo_param *hmacs;
541         __u16 n_elt;
542         __u16 id = 0;
543         int i;
544 
545         /* If we have a default entry, use it */
546         if (asoc->default_hmac_id)
547                 return &sctp_hmac_list[asoc->default_hmac_id];
548 
549         /* Since we do not have a default entry, find the first entry
550          * we support and return that.  Do not cache that id.
551          */
552         hmacs = asoc->peer.peer_hmacs;
553         if (!hmacs)
554                 return NULL;
555 
556         n_elt = (ntohs(hmacs->param_hdr.length) -
557                  sizeof(struct sctp_paramhdr)) >> 1;
558         for (i = 0; i < n_elt; i++) {
559                 id = ntohs(hmacs->hmac_ids[i]);
560 
561                 /* Check the id is in the supported range. And
562                  * see if we support the id.  Supported IDs have name and
563                  * length fields set, so that we can allocate and use
564                  * them.  We can safely just check for name, for without the
565                  * name, we can't allocate the TFM.
566                  */
567                 if (id > SCTP_AUTH_HMAC_ID_MAX ||
568                     !sctp_hmac_list[id].hmac_name) {
569                         id = 0;
570                         continue;
571                 }
572 
573                 break;
574         }
575 
576         if (id == 0)
577                 return NULL;
578 
579         return &sctp_hmac_list[id];
580 }
581 
582 static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
583 {
584         int  found = 0;
585         int  i;
586 
587         for (i = 0; i < n_elts; i++) {
588                 if (hmac_id == hmacs[i]) {
589                         found = 1;
590                         break;
591                 }
592         }
593 
594         return found;
595 }
596 
597 /* See if the HMAC_ID is one that we claim as supported */
598 int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
599                                     __be16 hmac_id)
600 {
601         struct sctp_hmac_algo_param *hmacs;
602         __u16 n_elt;
603 
604         if (!asoc)
605                 return 0;
606 
607         hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
608         n_elt = (ntohs(hmacs->param_hdr.length) -
609                  sizeof(struct sctp_paramhdr)) >> 1;
610 
611         return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
612 }
613 
614 
615 /* Cache the default HMAC id.  This to follow this text from SCTP-AUTH:
616  * Section 6.1:
617  *   The receiver of a HMAC-ALGO parameter SHOULD use the first listed
618  *   algorithm it supports.
619  */
620 void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
621                                      struct sctp_hmac_algo_param *hmacs)
622 {
623         struct sctp_endpoint *ep;
624         __u16   id;
625         int     i;
626         int     n_params;
627 
628         /* if the default id is already set, use it */
629         if (asoc->default_hmac_id)
630                 return;
631 
632         n_params = (ntohs(hmacs->param_hdr.length) -
633                     sizeof(struct sctp_paramhdr)) >> 1;
634         ep = asoc->ep;
635         for (i = 0; i < n_params; i++) {
636                 id = ntohs(hmacs->hmac_ids[i]);
637 
638                 /* Check the id is in the supported range */
639                 if (id > SCTP_AUTH_HMAC_ID_MAX)
640                         continue;
641 
642                 /* If this TFM has been allocated, use this id */
643                 if (ep->auth_hmacs[id]) {
644                         asoc->default_hmac_id = id;
645                         break;
646                 }
647         }
648 }
649 
650 
651 /* Check to see if the given chunk is supposed to be authenticated */
652 static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
653 {
654         unsigned short len;
655         int found = 0;
656         int i;
657 
658         if (!param || param->param_hdr.length == 0)
659                 return 0;
660 
661         len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
662 
663         /* SCTP-AUTH, Section 3.2
664          *    The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
665          *    chunks MUST NOT be listed in the CHUNKS parameter.  However, if
666          *    a CHUNKS parameter is received then the types for INIT, INIT-ACK,
667          *    SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
668          */
669         for (i = 0; !found && i < len; i++) {
670                 switch (param->chunks[i]) {
671                 case SCTP_CID_INIT:
672                 case SCTP_CID_INIT_ACK:
673                 case SCTP_CID_SHUTDOWN_COMPLETE:
674                 case SCTP_CID_AUTH:
675                         break;
676 
677                 default:
678                         if (param->chunks[i] == chunk)
679                                 found = 1;
680                         break;
681                 }
682         }
683 
684         return found;
685 }
686 
687 /* Check if peer requested that this chunk is authenticated */
688 int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
689 {
690         if (!asoc)
691                 return 0;
692 
693         if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
694                 return 0;
695 
696         return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
697 }
698 
699 /* Check if we requested that peer authenticate this chunk. */
700 int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
701 {
702         if (!asoc)
703                 return 0;
704 
705         if (!asoc->ep->auth_enable)
706                 return 0;
707 
708         return __sctp_auth_cid(chunk,
709                               (struct sctp_chunks_param *)asoc->c.auth_chunks);
710 }
711 
712 /* SCTP-AUTH: Section 6.2:
713  *    The sender MUST calculate the MAC as described in RFC2104 [2] using
714  *    the hash function H as described by the MAC Identifier and the shared
715  *    association key K based on the endpoint pair shared key described by
716  *    the shared key identifier.  The 'data' used for the computation of
717  *    the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
718  *    zero (as shown in Figure 6) followed by all chunks that are placed
719  *    after the AUTH chunk in the SCTP packet.
720  */
721 void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
722                               struct sk_buff *skb, struct sctp_auth_chunk *auth,
723                               struct sctp_shared_key *ep_key, gfp_t gfp)
724 {
725         struct sctp_auth_bytes *asoc_key;
726         struct crypto_shash *tfm;
727         __u16 key_id, hmac_id;
728         unsigned char *end;
729         int free_key = 0;
730         __u8 *digest;
731 
732         /* Extract the info we need:
733          * - hmac id
734          * - key id
735          */
736         key_id = ntohs(auth->auth_hdr.shkey_id);
737         hmac_id = ntohs(auth->auth_hdr.hmac_id);
738 
739         if (key_id == asoc->active_key_id)
740                 asoc_key = asoc->asoc_shared_key;
741         else {
742                 /* ep_key can't be NULL here */
743                 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
744                 if (!asoc_key)
745                         return;
746 
747                 free_key = 1;
748         }
749 
750         /* set up scatter list */
751         end = skb_tail_pointer(skb);
752 
753         tfm = asoc->ep->auth_hmacs[hmac_id];
754 
755         digest = auth->auth_hdr.hmac;
756         if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
757                 goto free;
758 
759         {
760                 SHASH_DESC_ON_STACK(desc, tfm);
761 
762                 desc->tfm = tfm;
763                 desc->flags = 0;
764                 crypto_shash_digest(desc, (u8 *)auth,
765                                     end - (unsigned char *)auth, digest);
766                 shash_desc_zero(desc);
767         }
768 
769 free:
770         if (free_key)
771                 sctp_auth_key_put(asoc_key);
772 }
773 
774 /* API Helpers */
775 
776 /* Add a chunk to the endpoint authenticated chunk list */
777 int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
778 {
779         struct sctp_chunks_param *p = ep->auth_chunk_list;
780         __u16 nchunks;
781         __u16 param_len;
782 
783         /* If this chunk is already specified, we are done */
784         if (__sctp_auth_cid(chunk_id, p))
785                 return 0;
786 
787         /* Check if we can add this chunk to the array */
788         param_len = ntohs(p->param_hdr.length);
789         nchunks = param_len - sizeof(struct sctp_paramhdr);
790         if (nchunks == SCTP_NUM_CHUNK_TYPES)
791                 return -EINVAL;
792 
793         p->chunks[nchunks] = chunk_id;
794         p->param_hdr.length = htons(param_len + 1);
795         return 0;
796 }
797 
798 /* Add hmac identifires to the endpoint list of supported hmac ids */
799 int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
800                            struct sctp_hmacalgo *hmacs)
801 {
802         int has_sha1 = 0;
803         __u16 id;
804         int i;
805 
806         /* Scan the list looking for unsupported id.  Also make sure that
807          * SHA1 is specified.
808          */
809         for (i = 0; i < hmacs->shmac_num_idents; i++) {
810                 id = hmacs->shmac_idents[i];
811 
812                 if (id > SCTP_AUTH_HMAC_ID_MAX)
813                         return -EOPNOTSUPP;
814 
815                 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
816                         has_sha1 = 1;
817 
818                 if (!sctp_hmac_list[id].hmac_name)
819                         return -EOPNOTSUPP;
820         }
821 
822         if (!has_sha1)
823                 return -EINVAL;
824 
825         for (i = 0; i < hmacs->shmac_num_idents; i++)
826                 ep->auth_hmacs_list->hmac_ids[i] =
827                                 htons(hmacs->shmac_idents[i]);
828         ep->auth_hmacs_list->param_hdr.length =
829                         htons(sizeof(struct sctp_paramhdr) +
830                         hmacs->shmac_num_idents * sizeof(__u16));
831         return 0;
832 }
833 
834 /* Set a new shared key on either endpoint or association.  If the
835  * the key with a same ID already exists, replace the key (remove the
836  * old key and add a new one).
837  */
838 int sctp_auth_set_key(struct sctp_endpoint *ep,
839                       struct sctp_association *asoc,
840                       struct sctp_authkey *auth_key)
841 {
842         struct sctp_shared_key *cur_key, *shkey;
843         struct sctp_auth_bytes *key;
844         struct list_head *sh_keys;
845         int replace = 0;
846 
847         /* Try to find the given key id to see if
848          * we are doing a replace, or adding a new key
849          */
850         if (asoc)
851                 sh_keys = &asoc->endpoint_shared_keys;
852         else
853                 sh_keys = &ep->endpoint_shared_keys;
854 
855         key_for_each(shkey, sh_keys) {
856                 if (shkey->key_id == auth_key->sca_keynumber) {
857                         replace = 1;
858                         break;
859                 }
860         }
861 
862         cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
863         if (!cur_key)
864                 return -ENOMEM;
865 
866         /* Create a new key data based on the info passed in */
867         key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
868         if (!key) {
869                 kfree(cur_key);
870                 return -ENOMEM;
871         }
872 
873         memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
874         cur_key->key = key;
875 
876         if (replace) {
877                 list_del_init(&shkey->key_list);
878                 sctp_auth_shkey_release(shkey);
879         }
880         list_add(&cur_key->key_list, sh_keys);
881 
882         return 0;
883 }
884 
885 int sctp_auth_set_active_key(struct sctp_endpoint *ep,
886                              struct sctp_association *asoc,
887                              __u16  key_id)
888 {
889         struct sctp_shared_key *key;
890         struct list_head *sh_keys;
891         int found = 0;
892 
893         /* The key identifier MUST correst to an existing key */
894         if (asoc)
895                 sh_keys = &asoc->endpoint_shared_keys;
896         else
897                 sh_keys = &ep->endpoint_shared_keys;
898 
899         key_for_each(key, sh_keys) {
900                 if (key->key_id == key_id) {
901                         found = 1;
902                         break;
903                 }
904         }
905 
906         if (!found || key->deactivated)
907                 return -EINVAL;
908 
909         if (asoc) {
910                 asoc->active_key_id = key_id;
911                 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
912         } else
913                 ep->active_key_id = key_id;
914 
915         return 0;
916 }
917 
918 int sctp_auth_del_key_id(struct sctp_endpoint *ep,
919                          struct sctp_association *asoc,
920                          __u16  key_id)
921 {
922         struct sctp_shared_key *key;
923         struct list_head *sh_keys;
924         int found = 0;
925 
926         /* The key identifier MUST NOT be the current active key
927          * The key identifier MUST correst to an existing key
928          */
929         if (asoc) {
930                 if (asoc->active_key_id == key_id)
931                         return -EINVAL;
932 
933                 sh_keys = &asoc->endpoint_shared_keys;
934         } else {
935                 if (ep->active_key_id == key_id)
936                         return -EINVAL;
937 
938                 sh_keys = &ep->endpoint_shared_keys;
939         }
940 
941         key_for_each(key, sh_keys) {
942                 if (key->key_id == key_id) {
943                         found = 1;
944                         break;
945                 }
946         }
947 
948         if (!found)
949                 return -EINVAL;
950 
951         /* Delete the shared key */
952         list_del_init(&key->key_list);
953         sctp_auth_shkey_release(key);
954 
955         return 0;
956 }
957 
958 int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
959                            struct sctp_association *asoc, __u16  key_id)
960 {
961         struct sctp_shared_key *key;
962         struct list_head *sh_keys;
963         int found = 0;
964 
965         /* The key identifier MUST NOT be the current active key
966          * The key identifier MUST correst to an existing key
967          */
968         if (asoc) {
969                 if (asoc->active_key_id == key_id)
970                         return -EINVAL;
971 
972                 sh_keys = &asoc->endpoint_shared_keys;
973         } else {
974                 if (ep->active_key_id == key_id)
975                         return -EINVAL;
976 
977                 sh_keys = &ep->endpoint_shared_keys;
978         }
979 
980         key_for_each(key, sh_keys) {
981                 if (key->key_id == key_id) {
982                         found = 1;
983                         break;
984                 }
985         }
986 
987         if (!found)
988                 return -EINVAL;
989 
990         /* refcnt == 1 and !list_empty mean it's not being used anywhere
991          * and deactivated will be set, so it's time to notify userland
992          * that this shkey can be freed.
993          */
994         if (asoc && !list_empty(&key->key_list) &&
995             refcount_read(&key->refcnt) == 1) {
996                 struct sctp_ulpevent *ev;
997 
998                 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
999                                                 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1000                 if (ev)
1001                         asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1002         }
1003 
1004         key->deactivated = 1;
1005 
1006         return 0;
1007 }
1008 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp